John Farley
Supporter
I managed to salvage a little out of a rather disappointing day. I have rarely seen severe weather parameters as favorable as they were today over Iowa, except (and a BIG except) for the cap.
Around 6 p.m., I noticed some TCU trying to bubble up south and southwest of the Waterloo-Cedar Falls area, along the outflow boundary/warm front that was moving northeastward across Iowa. They kept geting stopped by the cap and blown apart by the extreme wind shear. Only a few really made it past what you could call moderate cumulus before geting blown apart. However, it was obvious they were trying - how many times have you seen this with what could only be called a moderate cumulus cloud:
This was enough to get me to follow these clouds, to see if they could break the cap - obviously they wanted to. This is the same cloud a couple hours later, near Fayette:
At this point, it was just beginning to put down a few sprinkles - but the structure suggests the updraft was surely rotating. But the top just kept getting sheared off - but it was getting higher. In the meantime, a cell had popped up near New Hampton. I started for it at first, but figured I could not make it, so turned my attention back to the cloud I had been following, which looked like it was ready to go. But as I followed it northeast, I started to see lightning from the New Hampton cell as I entered West Union, and realized that it was moving fast enough I could catch it. But only barely before dark. I watched it a while north of West Union (north of the Turkey River crossing on route 150), and finally about midway between West Union and Decorah and a little after sunset around 9 p.m., it did this, off to my northeast:
This started as scud, but quickly became attached to the base, as shown in the first picture above. But the second one suggests it reverted back to scud pretty quickly. Both of the pictures are illuminated by lightning flashes, which was getting to be the only way you could see anything. In any case, this coincided with two events - the storm split, with the right split becoming the supercell that resulted in multiple tornado warnings from Prarie du Chein, Wi eastward, and around the time of the split, the first report of severe hail (1-inch) occurred in in Calmar, to my north and just west (left) of the lowering. So I do think the formation of this lowering was related to the storm's splitting and becoming a severe right-moving supercell. Not much, but better than nothing on a day that could have been so much more.
Full report coming as time allows - will post link.
Around 6 p.m., I noticed some TCU trying to bubble up south and southwest of the Waterloo-Cedar Falls area, along the outflow boundary/warm front that was moving northeastward across Iowa. They kept geting stopped by the cap and blown apart by the extreme wind shear. Only a few really made it past what you could call moderate cumulus before geting blown apart. However, it was obvious they were trying - how many times have you seen this with what could only be called a moderate cumulus cloud:
This was enough to get me to follow these clouds, to see if they could break the cap - obviously they wanted to. This is the same cloud a couple hours later, near Fayette:
At this point, it was just beginning to put down a few sprinkles - but the structure suggests the updraft was surely rotating. But the top just kept getting sheared off - but it was getting higher. In the meantime, a cell had popped up near New Hampton. I started for it at first, but figured I could not make it, so turned my attention back to the cloud I had been following, which looked like it was ready to go. But as I followed it northeast, I started to see lightning from the New Hampton cell as I entered West Union, and realized that it was moving fast enough I could catch it. But only barely before dark. I watched it a while north of West Union (north of the Turkey River crossing on route 150), and finally about midway between West Union and Decorah and a little after sunset around 9 p.m., it did this, off to my northeast:
This started as scud, but quickly became attached to the base, as shown in the first picture above. But the second one suggests it reverted back to scud pretty quickly. Both of the pictures are illuminated by lightning flashes, which was getting to be the only way you could see anything. In any case, this coincided with two events - the storm split, with the right split becoming the supercell that resulted in multiple tornado warnings from Prarie du Chein, Wi eastward, and around the time of the split, the first report of severe hail (1-inch) occurred in in Calmar, to my north and just west (left) of the lowering. So I do think the formation of this lowering was related to the storm's splitting and becoming a severe right-moving supercell. Not much, but better than nothing on a day that could have been so much more.
Full report coming as time allows - will post link.
Last edited by a moderator:
